Good morning, Thingy;

(Any relationship to James Arness?)

One nice thing about an f/1.2 lens is that very narrow DoF (Depth of Field). When you get it reasonably close, you know that it will be fine when the lens aperture stops down for the photograph. Helps a lot with eyes that are developing an excessive accumulation of years.

Like so many others, I also do not worry about any problems when focusing this kind of a lens with a "manually focusing camera."